Device for attaching a tool

ABSTRACT

A device for attaching a tool in portable angled grinders, allowing the connection to be released without special accessories. The device consists essentially of a hollow driveshaft, of a spindle that slides inside it, and of a tool-securing point consisting of a mating flange and nut. The nut is loosened by activating the displacing mechanism, which displaces the spindle toward the tool-securing point, lifting the nut, which is connected to the spindle by means of a threaded pin, off of the tool. The nut can then be screwed off by hand.

BACKGROUND OF THE INVENTION

The present invention relates to a device for attaching a tool inportable angled grinders, allowing the connection to be released withoutspecial accessories.

In order to replace the grinding disk in known angled grinders, theattaching flange, which is rigidly fastened to the grinding spindle,must be grasped with a special accessory. A mating flange, which isscrewed onto the grinding spindle, can then be loosened with anotheraccessory. This procedure is extremely inconvenient, entails the risk ofsevere injury, and is also very time-consuming.

German Pat. No. 2 926 469 accordingly proposes securing the grindingspindle with a mechanism that is integrated stationary into thedrive-mechanism housing. The advantage of that solution is that only oneaccessory is needed, to loosen the mating flange. Still, the accessoryfor loosening the mating flange may often be out of reach, and theoperator of an angled grinder of this type will be forced to look aroundfor it. Since accessories often get lost, many attempts are made inpractice to remove the tool by shear force, damaging the grinder.Furthermore, since the operator of a grinder of this type is not sparedthe necessity of carrying out a motion relative to the cutting edge ofthe tool with the hand that is holding the accessory, the risk of injuryremains just as high as with the older type of grinder.

Another disadvantage to the tool disclosed in that German patent is theexpense incurred in manufacture in order to prevent the grinder frombeing switched on unintentionally.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a device for attachinga tool to a manually operated angled grinder or similar electricimplement in such a way that no accessories are needed to establish orrelease the connection. The expense incurred in manufacture in order toprevent the grinder from being switched on unintentionally will also bereduced to a minimum.

This object is attained in accordance with the invention in that theangular drive mechanism, which is flanged to the motor of the angledgrinder and which consists essentially of a pinion, a beveled cogwheel,and a driveshaft, has a mechanism that can be used to displace a spindlepositioned inside the hollow driveshaft toward a securing point for thetool.

The axial displacement of the spindle lifts a nut, which forces the toolagainst the mating flange, away from the tool. The nut, which isknurled, can then easily be unscrewed from the spindle. No accessory isneeded to release the nut in this design. Furthermore, it costsapproximately as much to manufacture a displacing device of this type asit does to integrate a spindle-securing device stationary into thedrive-mechanism housing. Since the nut is directly hand-held and notscrewed on or off with an accessory while the tool is being inserted andextracted, the hand will not come into contact with the cutting edge,reducing the risk of injury.

In brief summary of the preceding description, a device for attaching atool to an angled grinder is disclosed wherein a displacing mechanism isactivated, axially displacing a spindle within a hollow driveshaft. Thedisplacing mechanism is located at one end of the spindle, the other endof which is threaded. The threading accommodates a nut. The nut forcesthe tool against a mating flange that is rigidly fastened to thedriveshaft. The driving motion of the shaft is accordingly transmittedto the tool.

The arrangement described above accordingly allows an essentiallysimpler procedure for replacing the tools than has previously beenpossible.

To accelerate and facilitate tool replacement even further, especiallywhen the grinder is to be operated by a robot, the device for attachingthe tool to the grinder can also be designed in such a way that the toolcan be replaced without turning a nut.

In this embodiment, the threaded fastening is replaced by an insertionfastening. To allow a securing bolt to be inserted into the spindle, abore with a cross-section that is similar to that of a facing pin on theface of the securing bolt is machined into the face of the spindle. Thespindle has, like a drill chuck, slots in the vicinity of the bore toallow the cheeks of this tensioning device to move radially. The radialmotion is produced by displacing the spindle axially inside the hollowdriveshaft by means of the displacing mechanism and allowing an externalconical surface in the slotted area of the spindle to slide over aninternal conical surface at a corresponding point on the driveshaft. Toattain a reliable positive connection between the pin and the bore, thesurface of the pin and the wall of the bore have transverse grooves toallow them to engage when radial pressure is applied to the slottedspindle.

There is a groove with a resilient snap-in structure mounted in it onthe surface of the securing bolt to ensure that the bolt has beeninserted far enough toward the securing point. The resilient snap-instructure snaps into a matching groove in the hollow driveshaft as soonas it arrives at that point. The securing bolt is designed in such a waythat it will rest loosely in the driveshaft when the snap-in point hasnot been reached, which makes it easy to tell when it must be inserteddeeper.

A further embodiment is provided so that, in an angled grinder with abraking device for example, the tool would not automatically come loosesubsequent to braking its rotation.

In accordance with the present invention, this embodiment is designedwith a bolt screwed into the face of the spindle, which is mounted insuch a way that it can be displaced axially inside the hollowdriveshaft. The end of the bolt that is remote from the spindle has aflange that forces the tool against the mating flange on the drive shaftthrough an intermediate bushing, which also has a flange. The bushinghas axial teeth along the surface of a cylindrical section. The teethmatch other teeth that extend over part of the inside surface of thehollow driveshaft. Between the flange on the bushing and the flange onthe bolt, the two surfaces are shaped to provide a positive connectionwhen they engage. The positive connection is not released until thedisplacing mechanism, through the spindle mounted inside the shaft,lifts the bolt away from the tool and hence the flange on the bolt awayfrom the flange on the bushing. This assumes, of course, that the stroketraveled by the displacing mechanism is longer than the toothed sectionbetween the flange on the bushing and on the bolt is deep.

Preferred embodiments of the invention will hereinafter be describedwith reference to the appended drawings. It is to be understood,however, that these are merely by way of example and that the scope ofthe protection sought for the invention is defined exclusively in theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal section through an angled grinder, with themotor represented only schematically,

FIG. 2 is a section along the line II--II in FIG. 1 and illustrates avariant,

FIG. 3 is in turn a variant of the device illustrated in FIG. 2,

FIG. 4 is a section along the line IV--IV in FIG. 3,

FIG. 5 is a longitudinal section through another embodiment of angledgrinder, with the motor represented only schematically, and

FIG. 6 is a section through the drive-mechanism housing of an angledgrinder with known drive-mechanism elements left out.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The angled grinder illustrated in FIG. 1 consists essentially of a motor14, represented truncated, of a connected drive mechanism 1, and of atool 23. The rotation of motor 14 is transmitted through a pinion 13 toa beveled cogwheel 15 that is connected to a driveshaft 16 in such a waythat it cannot rotate in relation to the shaft. Driveshaft 16 is mountedin two bearings 3 and 17 in opposite sides of a drive-mechanism housing2. At one end of driveshaft 16 is a displacing mechanism 6 that can beoperated from outside drive-mechanism housing 2. The other end ofdriveshaft 16 extends far enough out of drive-mechanism housing 2 for amating flange 22, which secures tool 23, to be rigidly connected to itscircumference. Driveshaft 16 is hollow to accommodate a spindle 20.Spindle 20 extends out beyond each face of driveshaft 16. At one end ofdriveshaft 16 spindle 20 engages with displacing mechanism 6 and at theother end with a threaded pin 19, onto which a nut 21 can be screwed.Mating flange 22 and nut 21 determine a securing point for tool 23. Tosynchronize driveshaft 16 with spindle 20, the spindle has teeth 18 forexample distributed over a certain area and meshing with other teethinside the driveshaft. This establishes a positive connection, ensuringthat spindle 20 will rotate in synchronization with driveshaft 16 whilestill allowing the spindle to move axially in relation to the shaft.

The axially displacement is produced by displacing mechanism 6. Thecylindrical appendage 9 of a lever 12 outside drive-mechanism housing 2is screwed into drive-mechanism housing 2. The threaded bore indrive-mechanism housing 2 and cylindrical appendage 9 are coaxial withspindle 20. Driveshaft 16, which is mounted in such a way that it canrotate in bearings 3 and 17, has, at the end that projects beyondbearing 3, a bushing-shaped cover 11 with a circular perforation forspindle 20 in its base 10. In the remaining space between the face ofdriveshaft 16 and the base 10 of bushing-shaped cover 11 is a spring 4that forces a concentric appendage 5 to spindle 20 against base 10. Theterminal component 7 of spindle 20 that extends through the perforationin base 10 projects into a depression 8 in cylindrical appendage 9.

When lever 12 pivots around the axis of cylindrical appendage 9, theappendage is screwed farther into or out of drive-mechanism housing 2.When it is screwed farther in, terminal component 7, and hence spindle20 as a whole, is displaced axially against the force of spring 4. Theaxial displacement lifts nut 21 from the lateral surface of tool 23.Since it is no longer necessary to overcome the compression between nut21 and tool 23 in order to release the nut, the latter, which can beknurled for example, can readily be screwed off of threaded pin 19manually.

To mount tool 23 it is positioned against mating flange 22 and nut 21 isscrewed onto threaded pin 19. How tightly the nut rests against the toolis unimportant. It will tighten on threaded pin 19 automatically oncethe motor is turned on.

If the operator neglects to pivot lever 12 back into its "closed"position, the facing surfaces of terminal component 7 and of depression8 are designed so that the friction between them will be sufficient toreturn the lever to that position when the motor is turned on.

It is also conceivable to employ another type of rotating element, aknob that clicks into "open" and "closed" positions for example, insteadof a lever if the pitch of the threading on cylindrical appendage 9 isappropriately selected.

FIGS. 2, 3, and 4 illustrate variants of the displacing mechanism 6illustrated in FIG. 1 that allow the drive-mechanism housing 2 to bekept smaller.

The spindle 20 in the variant illustrated in FIG. 2 is displaced axiallyby a displacing mechanism 25. Displacing mechanism 25 has a displacinghead 27 that can slide along rails 29 in drive-mechanism housing 2. Anaccess surface 26 on displacing head 27 extends through an aperture 28and beyond the outer contour of drive-mechanism housing 2. To preventdust from getting into drive-mechanism housing 2 for instance whendisplacing head 27 is displaced, the head has two protective strips 24,each of which extends over aperture 28. Displacing head 27 has a slopingsurface 30 on the side facing spindle 20. When displacing head 27 isdisplaced from the "closed" limiting position to the "open" limitingposition, sloping surface 30 slides over terminal component 31, forcingspindle 20 toward the tool-securing point.

The displacing mechanism 33 in the variants illustrated in FIGS. 3 and 4is designed in such a way that it cannot be unintentionally displacedfor example when the angled grinder is laid down. There are accordinglytroughs 32 in drive-mechanism housing 2 at the transitions between thetwo lateral surfaces and the side of the housing facing away from tool23. Troughs 32 have perforations that accommodate a sliding rod 35 thatcan be moved across the axis of driveshaft 16. Sliding rod 35 travelslaterally past a terminal component 34. When sliding rod 35 isdisplaced, a resilient structure 36 mounted at an angle on it forces abead on terminal component 34 toward the tool-securing point. Thus,sloping resilient structure 36 produces the same effect as the slopingsurface 30 in the variant illustrated in FIG. 2. As will be evident fromFIG. 4, terminal component 34 can rotate even when the operator hasforgotten to displace sliding rod 35 into the "closed" position beforeturning on the motor.

The designs described with reference to FIGS. 2, 3, and 4 especiallyfacilitate replacing the tool in the angled grinder. The compact designhardly increases the size of the housing at all. Reliability isincreased because the motor can be turned on without any component beingblocked inside the housing.

The angled grinder illustrated in FIG. 5 consists essentially of a motor14', a drive mechanism 1', and a tool .[.23.]. .Iadd.23'.Iaddend.. Therotation of motor 14' is transmitted to a beveled cogwheel 15' through apinion 13'. Beveled cogwheel 13' is mounted on a driveshaft 16' in sucha way that it can neither rotate in relation to the shaft nor slidealong it. Driveshaft 16' is mounted in two bearings secured in adrive-mechanism housing 2'.

A displacing mechanism 6' can axially displace a spindle 20' positionedinside the hollow driveshaft 16' as described with reference to FIG. 1.

There is a mating flange 22' that extends out of drive-mechanism housing2' on the end of driveshaft 16' that is remote from displacing mechanism.[.4'.]. .Iadd.6'.Iaddend.. Tool 23' rests against mating flange 22',whereupon a securing bolt 66' can be inserted through an accommodationaperture in tool 23' into hollow driveshaft 16'. The face of securingbolt 66' has a pin .[.67'.]. .Iadd.61' .Iaddend.that slips into amatching bore 60' in spindle 20' when securing bolt 66' is inserted indriveshaft 16'. Spindle 20' has slots 68' in the vicinity of bore 60'.Slots 68' make it possible to force the end of spindle 20' outwardradially. This force is generated when securing bolt 66' is inserted indriveshaft 16' and pin .[.67'.]. .Iadd.61' .Iaddend.slips into bore 60'.Displacing mechanism 6' is then displaced into the "closed" position,moving spindle 20' away from .[.tool'.]. .Iadd.tool 23'.Iaddend.. Pin.[.67'.]. .Iadd.61' .Iaddend.is then securely clamped into bore 60' inspindle 20' by an external conical surface 69' in the vicinity of slots68' in spindle 20' and by a matching internal conical surface 70' indriveshaft 16'. To ensure a positive connection, the surface of pin.[.67'.]. .Iadd.61' .Iaddend.and the wall of bore 60' have transversegrooves. Once pin .[.11'.]. .Iadd.61' .Iaddend.has been secured,securing bolt 66' as a whole is tensioned toward displacing mechanism6', securing tool 23'. To prevent relative rotation between driveshaft16' and securing bolt 66', both parts have matching teeth 63'.

A resilient snap-in structure .[.77'.]. .Iadd.71' .Iaddend.is insertedin a groove 64' that surrounds securing bolt 66'. Only when resilientsnap-in structure .[.77'.]. .Iadd.71' .Iaddend.engages a groove 67' inhollow driveshaft 16' has the point been attained at which a positiveconnection between pin .[.67'.]. .Iadd.61' .Iaddend.and spindle 20' canbe produced. The tolerances between securing bolt 66' and driveshaft 16'have been selected such that the bolt will otherwise lie loosely in theshaft.

The gear head 1" illustrated in FIG. 6 has a displacing mechanism 6"that extends on one side out of a drive-mechanism housing 2". Displacingmechanism 6" consists essentially of an activating mechanism 12" and astroke mechanism 9". Rotating activating mechanism 12" screws strokemechanism 9", which is rigidly connected to it, axially into or out of athread in drive-mechanism housing 2" in relation to a driveshaft 16"mounted in the housing. A spindle 20" is mounted in such a way as to bedisplaced axially inside the hollow driveshaft 16" as described in theforegoing against the force of resilient structures 4" by means ofdisplacing mechanism 6". Driveshaft 16" has at one end a bushing-shapedcover 11" with a circular perforation that accommodates spindle 20" inits base 10". In the remaining space between the face of driveshaft 16"and the base 10" of bushing-shaped cover 11", resilient structures 4"force a concentric appendage 5" to spindle 20" against base 10". Theterminal component 7" of spindle 20" that extends through theperforation in base 10" projects into a depression 8" in cylindricalappendage 9". A mating flange 22" is mounted on the end of driveshaft16" that is remote from displacing mechanism 6". A tool 23" restsagainst mating flange 22". An appendage on mating flange 22" centerstool 23". A flange 57" on a bolt 56" indirectly forces tool 23" againstmating flange 22" through a flange 53" on a bushing 54". The force isgenerated when bolt 56" in inserted through the cylindrical section 55"of bushing 54" and its front, which is threaded, screwed into matchingthreading inside spindle 20", subsequent to which the activatingmechanism 12" of displacing mechanism 6" is shifted into the "closed"position. The resulting pressure is sufficient to seat tool 23".

Hollow driveshaft 6" has a wider bore in the vicinity of mating flange22". The wall of the wider bore has longitudinal grooves 51". Matchingteeth 52" in the surface of the cylindrical section 55" of bushing 54"can be inserted in longitudinal grooves 51", ensuring positivetransmission of the rotation of driveshaft 16" to bushing 54".

To prevent bolt 56" from twisting out of the thread in spindle 20" whendriveshaft 16" is compulsorily braked, flanges 53" and 57" have radialteeth 58" and 50" on their facing surfaces. Teeth 58" and 50" ensurethat bolt 56" will rotate along with driveshaft 16" as long asactivating mechanism 12" remains in the "closed" position. Thecollar-like distribution of teeth 58" and 50" on the facing surfaces offlanges 53" and 57" ensures that the contact force can also be absorbedthrough flange 57".

To ensure that the operator can conveniently screw bolt 56" onto spindle20" it is recommendable for the edge of flange 57" to be designed suchthat it can easily be grasped with the hand. This can be done forexample by knurling it and/or covering it with a soft and resilientmaterial.

To remove tool 23", activating mechanism 12" must be shifted into the"open" position, whereupon displacing mechanism 6" will displace spindle20" against the force of resilient structures 4". The stroke will besufficient to disengage the teeth 50" on the flange 57" on bolt 56" fromthe teeth 58" on the flange 53" on bushing 54". Bolt 56" can then bescrewed out of spindle 20", bushing 54" extracted from driveshaft 16",and tool 23" replaced.

The invention has been described herein with reference to exemplaryembodiments. It will be understood, however, that it is receptable ofvarious modifications, which will offer themselves to those skilled inthe art and which are intended to be encompassed within the protectionsought for the invention as set forth in the appended claims.

We claim:
 1. Apparatus for attaching a tool in portable angled grinderscomprising a motor; angular drive means, and a securing station for thetool; said angular drive means comprising a pinion, a beveled cogwheel,and a hollow driveshaft having an axis; a spindle positioned in saiddriveshaft; housing means for housing said drive means; displacingmeans, said spindle being positioned in said driveshaft so that itcannot rotate .Iadd.relative to the driveshaft .Iaddend.but can bedisplaced axially from outside said housing means by said displacingmeans; activating means in said displacing means; traveling means and aterminal component, said spindle having an appendage; resilient meansbetween a face of said driveshaft and said appendage on said spindle,said activating means in said displacing means acting .[.through saidtraveling means at an angle to the axis of said driveshaft.]. on saidterminal component against a force of said .[.resilinet.]..Iadd.resilient .Iaddend.means .Iadd.by use of surface of said travelingmeans, said surface being inclined at an angle to the axis of saiddriveshaft.Iaddend.; said .[.driveshaft.]. .Iadd.spindle .Iaddend.havinga threaded pin; a nut screwed onto said threaded pin; a bushing-shapedcover on said driveshaft for limiting travel so that said nut screwedonto said threaded pin on said .[.driveshaft.]. .Iadd.spindle.Iaddend.is lifted away from the tool. .[.
 2. Apparatus according toclaim 1, wherein said spindle has teeth engaging inside the hollowdriveshaft..]. .[.3. Apparatus according to claim 1, including acylindrical appendage on said displacing means; said terminal componentbeing on said spindle; said housing means having a threaded bore; saidcylindrical appendage on said displacing means acting on said terminalcomponent to an extent that it is screwed into or out of said threadedbore in said housing means..]. .[.4. Apparatus according to claim 1,including a guide in said housing means, said displacing meanscomprising a displacing head slidable in said guide in said housingmeans; said displacing head having a sloping surface on a side extendinginto said housing means..]. .[.5. Apparatus according to claim 1,including a sliding rod and troughs with a perforation for accommodatingsaid sliding rod in edges between lateral surfaces and a surface of saidhousing facing toward the tool; said sliding rod having a springextending across a direction in which the rod slides in center of a sidefacing said terminal component..].
 6. Apparatus .[.according to claim 1,wherein.]. .Iadd.for attaching a tool in portable angled grinderscomprising a motor; angular drive means, and a securing station for thetool; said angular drive means comprising a pinion, a beveled cogwheel,and a hollow driveshaft having an axis; a spindle positioned in saiddriveshaft; housing means for housing said drive means; displacingmeans, said spindle being positioned in said driveshaft so that itcannot rotate relative to the driveshaft but can be displaced axially bysaid displacing means; activating means in said displacing means;traveling means and a terminal component, said spindle having anappendage; resilient means between a face of said driveshaft and saidappendage on said spindle, said activating means in said displacingmeans acting on said terminal component against a force of saidresilient means by use of a surface of said traveling means, saidsurface being inclined at an angle to the axis of said driveshaft;.Iaddend.said displacing means .[.can be activated.]. .Iadd.beingactivatable .Iaddend.from outside said housing means.[., said tool beingattachable in portable angled grinders with said displacing means thatcan be activated from outside said housing means.].; said spindle.[.being positioned in said hollow driveshaft and.]. having.[.tensioning means.]. .Iadd.clamping means .Iaddend.on an end remotefrom said displacing means .Iadd.for clamping said tool; said tool beingattachable with said displacing means that can be activated from outsidesaid housing means cooperating with said clamping means.Iaddend.. .[.7.Apparatus according to claim 6, wherein said spindle has slots forming adrill chuck and an external conical surface in vicinity of saidslots..]. .[.8. Apparatus according to claim 7, wherein said driveshafthas an internal conical surface in vicinity of said external conicalsurface..]. .[.9. Apparatus according to claim 7, wherein said spindlehas a bore of an end of said engine, said end having said slots..]..[.10. Apparatus according to claim 9, wherein said bore haspositive-locking means comprising transverse grooves in a wall of saidbore..]. .[.11. Apparatus according to claim 6, including a securingbolt connected releasably by said tensioning means to said spindle..]..[.12. Apparatus according to claim 11, wherein said spindle has an endface with a bore having a wall with grooves, said securing bolt having apin at an end toward said tensioning means, said pin having a surfacewith positive-locking means comprising transverse grooves engaging thegrooves in said wall of said bore..]. .[.13. Apparatus according toclaim 11, including resilient snap-in means, said securing bolt havingaround it a groove accommodating said resilient snap-in means..]. 14.Apparatus .[.according to claim 1, wherein the tool is attachable inportable angled grinders; stroke means; means for mounting said spindleto be displaceable axial but not rotatable in said hollow driveshaft,said spindle being displaceable by said displacing means from outsidesaid housing means, said activating means acting in said housing meansthrough said stroke means transversely to said axis of said driveshafton said terminal component against a force of said resilient means;.]..Iadd.for attaching a tool in portable angled grinders comprising amotor; angular drive means, and a securing station for the tool; saidangular drive means comprising a pinion, a beveled cogwheel, and ahollow driveshaft having an axis; a spindle positioned in saiddriveshaft; housing means for housing said drive means; displacingmeans, said spindle being positioned in said driveshaft so that itcannot rotate relative to the driveshaft but can be displaced axiallyfrom outside said housing means by said displacing means; activatingmeans in said displacing means; traveling means and a terminalcomponent, said spindle having an appendage; resilient means between aface of said driveshaft and said appendage on said spindle, saidactivating means in said displacing means acting on said terminalcomponent against a force of said resilient means by use of a surface ofsaid traveling means, said surface being inclined at an angle to theaxis of said driveshaft; .Iaddend.a bushing-shaped cover for limiting astroke and attached to said driveshaft; a bushing with a flange.[.lifted away from.]. .Iadd.for engaging .Iaddend.the tool.[.,.]..Iadd.; and .Iaddend.a bolt with a flange screwed into .[.anotherface.]. .Iadd.an end .Iaddend.of said spindle.[.and.]. .Iadd., saidbushing being .Iaddend.positively .[.connected by said flange on saidbolt through said flange on said bushing lifted away from the tool andthereby from the flange on said bushing.]. .Iadd.connectable with saidend of said spindle.Iaddend.. .[.15. Apparatus according to claim 1,wherein said bushing has surface with cylindrical section, saidcylindrical section having positive-locking means comprising teeth,parallel to an axis of said bushing..]. .[.16. Apparatus according toclaim 15, including teeth between both said flanges, said teeth having adepth which is less than a stroke of said displacing means..]. .[.17.Apparatus according to claim 14, wherein said bolt has means forproducing manipulation at an edge of said flange on said bolt..]. .[.18.Apparatus according to claim 16, wherein said teeth between said flangesextend over part of a radial expansion..]. .[.19. Apparatus according toclaim 14, wherein an end of said bolt remote from the flange on saidbolt is threaded..]. .[.20. Apparatus according to claim 14, whereinsaid spindle has a face with a threaded bore..]. .[.21. Apparatusaccording to claim 19, wherein said spindle has internal threads; theadson said bolt and the threads in said spindle being long enough foradapting to tools varying in thickness..]. .[.22. Apparatus according toclaim 14, including appendages on a mating flange, said tool beingcentered on said appendages on said mating flange and on said flange onsaid bushing..]. .Iadd.23. A tool driving unit for a portablepower-tool, comprising:a housing; a hollow outer spindle having an axis;an inner spindle within the outer spindle, one of the spindles beingslidable with respect to the other spindle in the axial direction of theouter spindle; tool holding means, connected to the outer spindle and tothe inner spindle, for releasably holding a tool, the tool holding meansincluding a first flange element connected to the outer spindle and asecond flange element connectable to the inner spindle at a positionadjacent the first flange element, the second flange element beingdetachable from the inner spindle; spring means for biassing the innerspindle and outer spindle with respect to each other to urge the flangeelements toward each other; an actuating element which is movable fromoutside the housing, by a manually applied force, between a releaseposition and an operating position; and release means, multiplying theforce applied to the actuating element, for acting on one of thespindles to displace said one of the spindles axially against the forceof the spring means when the actuating element is moved from itsoperating position toward its release position, the axial displacementmoving the flange elements apart so that the second flange element canbe manually detached from the inner spindle without tools, said releasemeans not acting on said one of the spindles when the actuating elementis in its operating position. .Iaddend. .Iadd.24. The tool driving unitof claim 23, wherein the release means comprises a pressure elementconnected to the actuating element, the pressure element having asurface with at least one portion which is inclined and extendstransverse to the axis of the outer spindle and which causes thepressure element to bear against the slidable spindle when the actuatingelement is moved from its operating position to its release position..Iaddend. .Iadd.25. The tool driving unit of claim 24, wherein thehousing has a threaded opening, wherein the pressure element has aperiphery, and wherein the at least one inclined portion of the surfaceof the pressure element comprises a thread on the periphery of thepressure element so that the pressure element screws into the threadedopening in the housing. .Iaddend. .Iadd.26. The tool driving unit ofclaim 24, wherein the at least one inclined portion of the surface ofthe pressure element faces the slidable spindle and slidably engages theslidable spindle as the actuating element is moved from its operatingposition to its release position. .Iaddend. .Iadd.27. The tool drivingunit of claim 24, wherein the actuating element is elongated and has anaxis, wherein the housing comprises means mounting the actuating elementfor axial movement, with the axis of the actuating element beingtransverse to the axis of the outer spindle, and wherein the at leastone inclined portion of the surface of the pressure element istransverse to the axis of the actuating element in addition to beingtransverse to the axis of the outer spindle. .Iaddend. .Iadd.28. Thetool driving unit of claim 23, wherein the inner spindle has a threadedend, and wherein the second flange element has a threaded opening topermit the second flange element to be detachably screwed onto thethreaded end of the inner spindle. .Iaddend. .Iadd.29. The tool drivingunit of claim 23, further comprising keying means for locking thespindles together with respect to rotation, so that rotation of onespindle causes the other to rotate. .Iaddend. .Iadd.30. The tool drivingunit of claim 23, wherein the outer spindle has an end, and furthercomprising an appendage on the inner spindle, the appendage being spacedapart from the end of the outer spindle, and wherein the spring means isdisposed between the end of the outer spindle and the appendage on theinner spindle. .Iaddend. .Iadd.31. The tool driving unit of claim 23,further comprising means attached to one of the spindles and cooperatingwith the other of the spindles for limiting sliding movement between thespindles. .Iaddend. .Iadd.32. The driving unit of claim 23, wherein thetool holding means additionally comprises clamping means, actuatable bya sliding movement of the spindles when the actuating element is movedfrom the release position toward the operating position, for grippingthe second flange element after it has been manually placed in areceiving position adjacent the clamping means. .Iaddend. .Iadd.33. Thedriving unit of claim 23, wherein the tool holding means furthercomprises bushing means, disposed between the flange elements andcontacting the second flange element, for isolating the second flangeelement from torque. .Iaddend. .Iadd.34. A portable power-tool forspinning an exchangeable working tool, comprising:a housing having anopening; a hollow outer spindle in the housing, the outer spindle havingan axis which extends through the opening; an inner spindle disposed inthe outer spindle, one of the spindles being displaceable in the axialdirection with respect to the other spindle; a first flange element;means for mounting the first flange element to the outer spindle so thatthe first flange element is disposed outside the housing and adjacentthe opening; a second flange element; means for detachably mounting thesecond flange element to the inner spindle so that the second flangeelement is disposed outside the housing adjacent the first flangeelement; spring means for biassing the displaceable spindle to clamp aworking tool that has been placed between the flange elements; anactuating member having a manually engageable portion and having acontact area; and means for mounting the actuating member so that thecontact area is adjacent the displaceable spindle and the manuallyengageable portion extends outside the housing, the manually engageableportion being manually movable along a path between an operatingposition and a release position, the contact area, in the course of saidmovement of said manually engageable portion from the operating positiontoward the release position, being moved over a distance shorter thansaid path and pressing against the displaceable spindle to slide thedisplaceable spindle against the force of the spring means so that thesecond flange element can be manually detached during an exchange ofworking tools. .Iaddend. .Iadd. The portable power-tool of claim 34,wherein the actuating member comprises a lever, and wherein the meansfor mounting comprises means for rotatably mounting the lever on thehousing. .Iaddend. .Iadd.36. The portable power-tool of claim 34,wherein the actuating member is movable in a direction transverse to theaxis of said hollow spindle, and wherein the means for mountingcomprises means for guiding the actuating member on the housing so thatthe actuating member is slidable along that direction. .Iaddend..Iadd.37. The portable power-tool of claim 34, further comprising acover element attached to the outer spindle, the cover element having anopening through which the inner spindle extends, and wherein the springmeans is disposed inside the cover element. .Iaddend. .Iadd.38. Theportable power-tool of claim 34, wherein the means for detachablymounting the second flange element additionally comprises clampingmeans, actuatable by movement of the displaceable spindle when themanually engageable portion of the actuating member is moved from itsrelease position toward its operating position, for gripping the secondflange element after it has been manually placed in a receiving positionadjacent the clamping means. .Iaddend. .Iadd.39. The portable power-toolof claim 38, wherein the means for detachably mounting the second flangeelement additionally comprises means, extending parallel to the axis ofthe outer spindle, for keying the second flange element to the outerspindle so that the second flange element is slidable but not rotatablewith respect to the outer spindle. .Iaddend. .Iadd.40. The portablepower-tool of claim 34, wherein the working tool has an opening throughwhich the means for detachably mounting extends, and further comprisinga bushing member between the second flange element and the working tool,and means extending through the opening in the working tool for keepingthe bushing member from rotating with respect to the outer spindle..Iaddend. .Iadd.41. A tool driving unit for a power-tool comprising:ahollow outer spindle having an axis; an inner spindle within the outerspindle, one of the spindles being slidable in the axial direction withrespect to the other spindle; means for selectively shifting one of thespindles with respect to the other spindle between a release positionand a clamp position; and tool holding means, connected to the spindles,for releasably holding a tool, the tool holding means including a firstflange element connected to one of the spindles, a second flangeelement, and clamping means, connected to the other spindle andactuatable by a shifting movement of the spindles from the releaseposition toward the clamp position, for gripping the second flangeelement after it has been manually placed in a receiving positionadjacent the clamping means and for moving the second flange elementtoward the first flange element to clamp the tool between the flangeelements. .Iaddend. .Iadd.42. The tool driving unit of claim 41, whereinthe clamping means comprises gripping appendages attached to said otherspindle. .Iaddend. .Iadd.43. The tool driving unit of claim 42, whereinthe gripping appendages are actuatable by a flared portion either at thegripping appendages or at said one of the spindles. .Iaddend. .Iadd.44.The tool driving unit of claim 43, wherein the first flange element isconnected to the outer spindle, wherein the outer spindle has a flaredportion; and wherein the gripping appendages comprise an end portion ofthe inner spindle, the end portion being flared and fitting within theflared portion of the outer spindle, the end portion of the innerspindle having a bore and having at least one slot which extends outwardfrom the bore for forming the gripping appendages. .Iaddend. .Iadd.45.The tool driving unit of claim 44, wherein the second flange elementcomprises a flange portion, a pin portion which fits into the bore, anda connecting portion between the flange portion and the pin portion, andwherein the clamping means further comprises at least one abutment onthe pin portion, and at least one abutment which is attached to thegripping appendages to grip onto the at least one abutment on the pinportion when the spindles are selectively shifted from their releaseposition to their clamp position. .Iaddend. .Iadd.46. The tool drivingunit of claim 45, wherein the at least one abutment attached to thegripping appendages comprises a plurality of annular ridges whichproject into the bore, and wherein the at least one abutment on the pinportion comprises plurality of annular ridges. .Iaddend. .Iadd.47. Thetool driving unit of claim 45, wherein the connecting portion has anannular groove between the pin portion and the flange portion, andfurther comprising a stop ring in the annular groove. .Iaddend..Iadd.48. The tool driving unit of claim 45, further comprising meansfor keying the connecting portion to the outer spindle so that theconnecting portion cannot rotate with respect to the outer spindle..Iaddend. .Iadd.49. The tool driving unit of claim 41, wherein the meansfor selectively shifting comprises:spring means for biassing thespindles toward the clamp position; an actuating member having amanually engageable portion and having a contact area; and means formounting the actuating member so that the actuating member is movablebetween first and second positions by a force manually applied to themanually engageable portion, the contact area of the actuating memberpressing on the slidable spindle to shift the spindles from the clampposition toward the release position when the actuating member is movedfrom its first position toward its second position, the force exerted bythe contact area on the slidable spindle when the actuating member ismoved from its first position toward its second position being greaterthan the force applied to the manually engageable portion to move theactuating member from its first position to its second position..Iaddend. .Iadd.50. A tool driving unit for a power-tool, comprising: adrive member having an axis; and tool holding means, connected to thedrive member, for releasably holding a tool, the tool holding meansincludinga first clamping flange affixed to the drive member; a bushingflange, a second clamping flange, means for detachably connecting thesecond clamping flange to the drive member, with the second clampingflange pressing the bushing flange toward the first clamping flange, andwith the tool being disposed between the bushing flange and the firstclamping flange, and keying means for non-rotatably holding the bushingmember with respect to the first clamping flange while permitting thebushing flange to move axially with respect to the drive member..Iaddend. .Iadd.51. The tool driving unit of claim 50, wherein the drivemember comprises a hollow outer spindle, and an inner spindle which isslidably disposed in the outer spindle, wherein the first clampingflange is affixed to the outer spindle, and wherein the means fordetachably connecting the second clamping flange to the drive membercomprises means for detachably connecting the second clamping flange tothe inner spindle. .Iaddend. .Iadd.52. The tool driving unit of claim51, further comprising;spring means for biassing the inner spindle awayfrom the first clamping flange so as to urge the second clamping flangetoward the tool; an actuating member having a manually engageablyportion and having a contact area; and means for mounting the actuatingmember so that the contact area is adjacent the inner spindle and sothat the manually engageable portion is manually movable along a pathbetween an operating position and a release position, the contact area,in the course of said movement of said manually engageable portion fromthe operating position toward the release position, being moved over adistance shorter than said path and pressing against the inner spindleto slide the inner spindle toward the first clamping flange against theforce of the spring means so that the second flange element can bemanually detached. .Iaddend. .Iadd.53. The tool driving unit of claim52, wherein the tool has an opening, and wherein the means fordetachably connecting the second clamping flange to the inner spindlecomprises a threaded bolt which extends through the opening in the tool..Iaddend. .Iadd.54. The tool driving unit of claim 53, wherein thekeying means comprises a keying element which contacts the bushingflange and which extends through the opening in the tool. .Iaddend..Iadd.55. The tool driving unit of claim 54, wherein the keying elementcomprises a hollow sleeve affixed to the bushing flange, the threadedbolt extending through the hollow sleeve. .Iaddend. .Iadd.56. The tooldriving unit of claim 55, wherein the bushing flange has a surface whichcontacts a surface of the second clamping flange, and further comprisingfurther keying elements on the surface of the bushing flange whichcontacts the second clamping flange, and additional keying elements onthe surface of the second clamping flange which contacts the bushingflange. .Iaddend. .Iadd.57. The tool driving unit of claim 56, whereinthe further keying elements on the bushing flange and the additionalkeying elements on the second clamping flange have a keying depth thatis selected so that the further keying elements on the bushing flangeare spaced apart from the additional keying elements on the secondclamping flange when the actuating member is in its release position..Iaddend. .Iadd.58. The tool driving unit of claim 50, wherein the toolhas an opening through which the means for detachably connectingextends, and wherein the keying means comprises a keying element whichcontacts the bushing flange and which extends through the opening in thetool. .Iaddend. .Iadd.59. The tool driving unit of claim 58, wherein themeans for detachably connecting comprises a threaded bolt, and whereinthe keying element comprises a hollow sleeve attached to the bushingflange, the threaded bolt extending through the hollow sleeve. .Iaddend..Iadd.60. The tool driving unit of claim 59, wherein the keying meansfurther comprises at least one abutment on the hollow sleeve, and atleast one further abutment on one of the inner spindle, outer spindle,and first clamping flange to slidably engage the at least one abutmenton the hollow sleeve. .Iaddend.